Hapax

In corpus linguistics, a hapax legomenon (/ˈhæpəks lᵻˈɡɒmᵻnɒn/ also /ˈhæpæks/ or /ˈheɪpæks/; pl. hapax legomena; sometimes abbreviated to hapax, pl. hapaxes) is a word that occurs only once within a context, either in the written record of an entire language, in the works of an author, or in a single text. The term is sometimes incorrectly used to describe a word that occurs in just one of an author's works, even though it occurs more than once in that work. Hapax legomenon is a transliteration of Greek ἅπαξ λεγόμενον, meaning "(something) said (only) once".

The related terms dis legomenon, tris legomenon, and tetrakis legomenon respectively (/ˈdɪs/, /ˈtrɪs/, /ˈtɛtrəkᵻs/) refer to double, triple, or quadruple occurrences, but are far less commonly used.

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